#!/bin/bash
echo "enter the first no"
read first
echo "enter the second no"
read second
echo "enter the operation"
read ch
case $ch in
"+")res=`expr $first + $second`;;
"-")res=`expr $first - $second`;;
"*")res=`expr $first \* $second`;;
"/")res=`expr $first / $second`;;
esac
echo "result is "$res 
